Avelumab in patients with previously treated mesothelioma: Updated phase 1b results from the JAVELIN Solid Tumor trial.

Abstract

166 Background: Avelumab, a human anti-PD-L1 IgG1 monoclonal antibody, is approved for treatment of metastatic Merkel cell carcinoma (US and EU) and advanced urothelial carcinoma progressed on platinum therapy (US). Here, we report updated phase 1b data for avelumab in patients (pts) with previously treated mesothelioma. Methods: Pts with unresectable pleural or peritoneal mesothelioma whose disease had progressed after platinum and pemetrexed therapy received avelumab 10 mg/kg IV Q2W until progression, unacceptable toxicity, or withdrawal. Tumors were assessed every 6 wks (RECIST 1.1). Endpoints included objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and adverse events (AEs; NCI CTCAE v4.0). Results: As of Dec 31, 2016, 53 pts were treated and followed for a median of 24.8 mos (range 16.8–27.8). Median age was 67 y (range 32–84). Pts had received a median of 2 prior lines of therapy (range 1–8). Confirmed ORR was 9.4% (95% CI 3.1–20.7; complete response in 1.9%, partial response in 7.5%). In pts with 1 (n = 18), 2 (n = 15) or ≥3 (n = 20) prior lines of therapy, ORR was 5.6%, 13.3% and 10.0% respectively. Median duration of response was 15.2 mos (95% CI 11.1–not estimable). 26 pts (49.1%) had stable disease as best response and the disease control rate was 58.5%. Median PFS was 4.1 mos (95% CI 1.4–6.2) and the 6-mo PFS rate was 38.0% (95% CI 24.2–51.7). Median OS was 10.9 mos (95% CI 7.5–21.0) and the 12-mo OS rate was 45.9% (95% CI 31.9–58.8). In evaluable pts with PD-L1+ (n = 16) and PD-L1− (n = 27) tumors (≥5% tumor cell cutoff), ORR was 18.8% (95% CI 4.0–45.6) and 7.4% (95% CI 0.9–24.3), and the 6-mo PFS rate was 37.5% (95% CI 14.1–61.2) and 42.0% (95% CI 23.1–59.8). 43 pts (81.1%) had a treatment-related (TR)AE, most commonly ( > 10%) infusion-related reaction (35.8%; all grade 1/2), chills (15.1%), fatigue (15.1%) and pyrexia (11.3%). 5 pts (9.4%) had a grade ≥3 TRAE. 14 pts (26.4%) had an immune-related AE, which was grade ≥3 in 3 pts (5.7%; pneumonitis, colitis, and type 1 diabetes mellitus). No treatment-related deaths occurred. Conclusions: Avelumab showed clinical activity and acceptable safety in pts with previously treated mesothelioma. Clinical trial information: NCT01772004.